As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Examples of portable information handling systems include notebook computers. Circuitry of these portable electronic devices are typically powered by battery systems such as lithium ion (“Li-ion”) or nickel metal hydride (“NiMH”) battery packs including one or more rechargeable battery cells. Battery cells, such as rechargeable Li-ion cells are commonly constructed by winding a negative electrode, positive electrode and intervening separator into a layered structure that is referred to as a “jelly roll”, and placing this spirally wound jelly roll assembly into a container. FIG. 1 illustrates an end view of a typical rechargeable Li-ion jelly roll structure 100, with terminal end sections 100a and 100b circled.
FIG. 2 shows conventional layered construction of sections 100a and 100b of battery structure 100 when unrolled. As shown in FIG. 2, Li-ion battery structure 100 includes three major parts that are active in the charge/discharge activity, negative electrode 202, positive electrode 204 and separator 206. Positive electrode 204 includes a conductive current carrier (substrate) 214 such as aluminum, and a positive active electrode coating 216 such as lithium cobalt oxide (Li—Co oxide). As further shown in FIG. 2, positive electrode 204 includes uncoated areas 215 which are used for handling and connection areas to form a current path from the current collector to the external contacts of the cell. Negative electrode 202 is constructed in a similar manner to positive electrode 204, though the surface area of negative electrode 202 is typically larger than the surface area of positive electrode 204. Negative electrode 202 includes a conductive current carrier 210 such as copper, and a negative active electrode coating 212 such as carbon graphite. In a manner similar to positive electrode 204, negative electrode 202 includes uncoated areas 211 that are provided for handling and connection areas. Porous separator 206, such as polypropylene or polyethylene, provides electrical insulation between negative electrode 202 and positive electrode 204, while at the same time allowing transfer of ions between electrodes 204 and 202. When separator 206 is conductively breached, the result can range from degradation of the battery cell to a thermal runaway.
In an attempt to prevent separator failures, some jelly roll battery structures have been provided with a thickened separator material, or with layered separator materials to increase puncture strength. However, use of thicker separator materials reduces the capacity of a battery cell due to the increased volume occupied by the separator material.